Clockwork mechanism, especially alarm clock mechanism

ABSTRACT

A clockwork mechanism is provided having an axially shiftable and rotatable adjustment shaft. The shaft is provided at one end with two resilient axially extending projections which have wedge-shaped elements formed on the terminal ends thereof. A knob is provided and is formed with an axial bore having an internal shoulder disposed therein. When the shaft is inserted within the axial bore of the knob, the projections are wedged together until the wedge-shaped elements expand and engage within the wider portion of the bore defined by the internal shoulder thereof. To release the knob from the shaft, a pincer tool is inserted into the bore and the ends of the projections are forced together to disengage them from the internal shoulder. The other axial end of the shaft may be formed with an axial bore which slides and rotatingly about a pivot pin extending normally from a baseplate of the mechanism.

I United States Patent m1 3,603,077

[72] Inventor Wolfgang Canter 2,978,927 4/196] Blanton l6/I2l Schramberg-Sulgen, Germany 3,498,046 3/1970 .lepson et al. 58/l6 I 1 259p; No. 277,1 1969 FOREIGN PATENTS 22 i e in. Patented Sept 7 197] 69,941 9/1915 Austria 58/855 [73] Assignee Messrs. Gebrueder Junghans GmbH Primary Examiner-Richard B. Wilkinson Schramberg, Germany Assistant ExaminerLawrence R. Franklin [32] Priority Nov. [8, I968 Att0rneyBurns, Doane, Sweckerdz Mathis [33] Germany 31 1 68 07 494 M ABSTRACT: A clockwork mechanism is provided having an [54] CLOCKWORK MECHANISM ESPECIALLY axially shiftable and rotatable adiustment shaft. The shal't is ALARM CLOCK MECHANISM protrlded at one end wlth two resilient axially extending pro- 6 Claims 4Dmwing Figs ections wh|ch have wedge-shaped elements formed on the termmal ends thereof. A knob is provided and 18 formed with an axial bore having an internal shoulder disposed therein. lfi/lzl 53/35-5 When the shaft is inserted within the axial bore of the knob, [51] Int. Cl ..G04b 27/00 the projections are wedgad together the wedge 5haped [50] Field of Search 58/7, 16, elements expand and engage within the wide, portion f the i9, 53, 85-5, 225; 16/118, 1213 85/5, bore defined by the internal shoulder thereof. To release the knob from the shaft, a pincer tool is inserted into the bore and [56] References Cited the ends of the projections are forced together to disengage UNITED STATES PATENTS them from the internal shoulder The other axial end of the 797,918 8/1905 Schehr l6/l2l shaft may be formed with an axial bore which slides and 2,721,44l l0/l955 Boyles 58/]9 rotatingly about a pivot pin extending normally from a 2,863,968 l2/l958 Trautman 16/] I8 baseplate ofthe mechanism.

CLOCKWORK MECHANISM, ESPECIALLY ALARM CLOCK MECHANISM BACKGROUND OF THE INVENTION The invention relates to clockwork mechanisms, especially alarm clock mechanisms and it concerns a mechanism of that known design whose hands can be adjusted by means of at least one adjusting shaft, onto which an adjusting knob with releasable coupling has been placed. It is the purpose of the invention to improve the coupling for the adjusting knob, but furthermore also to improve the mounting and development of the adjusting shaft itself. Customarily, the adjusting knob is screwed onto the adjusting shaft for the purpose of its coupling with it, and this results in the disadvantage that the coupling is effective only in one rotational direction, while the danger exists that the adjusting knob will disengage from the adjusting shaft. Another type of attachment in which a square end is squeezed onto the adjusting shaft and the adjusting knob is provided with a slit plug socket, has the disadvantage that the adjusting knob must be pressed uninterruptedly onto the square end so that it will not disengage itself unintentionally. However, this type of attachment is insufficient especially whenever, as for example in the case of travel alarm clocks, the adjusting shaft for the hands carries out a double function, namely whenever it is coupled in one position, for example, with the adjusting edge of the alarm clock, and in another position achieved through its axial shifting is coupled with the change gear of the drive for the hands. In that case there exists the danger especially that upon repeated operation of the adjusting shaft the adjusting knob will get lost.

SUMMARY AND OBJECTS OF THE INVENTION The invention eliminates these and other disadvantages of the hitherto customary adjusting shafts through the fact that, at the end of the coupling of the adjusting shaft and the adjusting knob having an axial passage, radially engaging expanding means, accessible at the rear opening of the passage of the adjusting knob, have been provided besides paraxial border surfaces engaging in a positively locking manner, as well as a shelf on the shaft constituting an inner support for the adjusting knob. As a result of that the adjusting knob has been coupled with the adjusting shaft for the transmission of revolving and thrusting forces in a manner that it cannot get lost. Since the expanding means are accessible at the rear opening of the adjusting knob, they can be put into their nonexpanding position by means of a suitable tool, so that the adjusting knob can be pulled off the shaft. In a further development of the invention for the purposes of an alarm clock, whose adjusting shaft is shifted axially by means of the adjusting knob for the purpose of an adjustment of the hands indicating time or setting the alarm, said adjusting shaft at its other end besides the coupling end has a tip-stretched tooth wheel drive for the alternate engagement with the adjusting wheel for the alarm clock or the change gear for the hands and has furthermore an axial dead end bore, with which it is guided on a bearing pin which is tipstretched on the baseplate bar, and is therefore fixed. For practical purposes, a disk-shaped collar is formed onto the adjusting knob, which together with a perforation in the rear wall of the housing corresponding to it, constitutes a seal against dust getting into the clockwork mechanism. The adjusting shaft and the adjusting knob according to the invention may be made from any desired raw material; but a design made of plastic is preferred in accordance with the invention.

DESCRIPTION OF THE DRAWING Further characteristics and advantages of the invention will result from the subsequent description of a design given by way of example in the drawing and from the patent claims. Each time at an enlarged scale:

FIG. I shows the parts of the drive for the hands and the adjusting means for the hands of an alarm clock mechanism,

which are essential for an understanding of the invention, together with the axially shiftable adjusting shaft in side view;

FIG. 2 shows the adjusting shaft with an adjusting button put on in a lateral sectional view, once more enlarged in com parison to FIG. I;

FIG. 3 shows the adjusting shaft in front view of the adjusting button; and

FIG. 4 shows the coupling end of the adjusting shaft in a perspective presentation.

DETAILED DESCRIPTION The clockwork mechanism illustrated (partially) in FIG I of the drawing consists of the baseplate II, the intermediate plates 12 and 13 and the rear wall I4 of the housing. Support pillars 15 hold the above-mentioned parts together. Between the plates 12 and 13 and partially I2 and II, the driving mechanism for the second hand 16, the minute hand I7, the hour hand I8 and the alarm hand I9 are mounted. 20 is the adjusting wheel for the alarm, 21 the change wheel of the driving system for the hands indicating time. The adjusting shaft 22 has a shaft element 22a with which it is mounted axially shiftably in the plate 13. The gear drive 22b has been formed onto the front end of the adjusting shaft 22 facing the hands [6 to 19. It is intended to be in engagement with the alarm-adjusting wheel 20 in the forward position of the adjusting shaft (FIG. I), in retracted position on the other hand to be in en gagement with the change wheel 21 of the drive for the hands indicating time. A pressure spring 23 built in with pretension holds the adjusting shaft in its front position. A perforation I20 has been provided in the plate I2, which allows the gear drive 22!: to pass through in the case of an axial shifting of the adjusting shaft 22. For mounting the front end of the adjusting shaft 22, a pivot journal Ila has been formed to the inside of the baseplate I], said pivot engaging with a dead end bore 22c in the front side of the adjusting shaft 22.

The coupling end of the adjusting shaft 22 is somewhat recessed so that a support surface 22d will develop, on which the adjusting knob 24 is seated with the front surface 24a of the collar 24b for sealing against dust. Laterally to the coupling end of the adjusting shaft 22, a pair of paraxial edge surfaces 22c have been formed. The knob 24 has an axial passage equipped with counter surfaces 24c which fit in a posi tively locking manner. The coupling end of the adjusting shaft 22 has furthermore been slit at 22fand has been provided with expanding hooks 22g pointing radially outwardly, which engage positively locking in the coupling position via supporting surfaces 24d, which are formed by an enlargement of the axial passage of the knob. Through the expansion means, the ad justing knob 24 is coupled in a positively locking manner with the adjusting shaft 22 for the transmission of axial forces. In order to be able to pull the knob 24 from the adjusting shaft 22, rear seat surfaces 223 have been attached to the expanding hooks 22g. A pair of pincers for example is applied to these, the expanding hooks are compressed resiliently and as a result the hooks 22g are lifted off the supporting surfaces 2411 on the knob, so that the knob can be pulled off. When pushing the knob 24 onto the adjusting shaft 22, the surfaces 22!! serve as sliding guide surfaces for the resilient compression of the hooks and introduction of the knob into the axial passage. The collar 24b formed onto the adjusting knob 24 fits in a dust proof manner into the perforation 14a in the rear wall I4 of the housing.

The assembly of the adjusting shaft 24 is accomplished as follows: While the base plate II is still lifted off the frame 12/13/15, the adjusting shaft 22 with washer 25 already pushed into it and with the feeder spring 23 will be slid into the frame. Now the adjusting wheel 20 for the alarm and the hour wheel 26 are inserted. Now the baseplate I1 is put on in such a manner that its pivot journal IIa reaches the front bore 22c of the adjusting shaft. Then the adjusting knob 24 is pressed from the rear side of the clockwork mechanism onto the coupling end of the adjusting shaft 22, until the expansion hooks 22g reach beyond the supporting surfaces 24d on the knob.

By way of summary, it will be recognized that knob surface means 24d may be viewed as abutment means engaged by locking means 22g of the shaft 22. In addition, shaft surface means 222 may be viewed as first surface means disposed in complementary and usually abutting engagement with second surface means 24c of the knob 24. The mutual abutting engagement which occurs between the surface means 22:: and 24c in response to knob rotation serves to prevent rotation of the knob relative to the shaft in each of opposite directions of knob rotation so as to ensure unitized rotation of the knob and shaft.

What is claimed is:

1. In a clockwork mechanism having hands adjustable by a shaft assembly, said shaft assembly comprising:

a shaft;

a knob;

said knob being releasably coupled to a first portion of said shaft,

said knob being formed with an axial bore, and

said knob having abutment means extending generally transversely of said axial bore;

mutually abuttable first and second surface means carried by said shaft and said knob respectively and operable, in

response to mutual abutment therebetween, to prevent rotational movement of said knob relative to said shaft in each of opposite directions of knob rotation;

said shaft being formed with radially expanding means;

said radially expanding means being provided with locking means,

said locking means being lockingly engageable with said transversely extending abutment means to prevent axial movement of said knob relative to said shaft and permit axial movement of said knob to induce axial movement of said shaft, and

said locking means being operably accessible at an outer end of said axial bore of said knob when said knob is mounted on said shaft.

2. A clockwork mechanism according to claim 1 wherein:

said first portion of said shaft is provided with a longitudinal slot to form two expandable resilient projections, which projections define said locking means;

the terminal ends of said projections are formed with radi ally extending portions whereby said projections are generally hooklike in configuration; and said axial bore in said knob is formed with an internal shoulder, defining said abutment means, for lockingly retaining the radially extending portions of the terminal ends of said projections when said knob is mounted on said shaft. 3, A clockwork mechanism according to claim 2: wherein each said radially extending portion of each said projection is formed with a partial frustoconical surface tapered toward the terminal end of each said projection whereby said resilient projections are forced together by a wedging action on said surfaces by the internal surface of said knob defining said axial bore as said shaft is forced into said axial bore of said knob; and wherein a tool may be inserted within said axial bore to engage said frustoconical surfaces of said projections to force said projections together to disengage said projections from within said axial bore. 4. In a clockwork mechanism according to claim I wherein: said shaft assembly is axially shiftable; a second portion of said shaft is formed with a pinion drive portion; said pinion drive portion being alternately engageable with an alarm-adjusting gearwheel and a time-indicating hand adjustment as said shaft is axially shifted; said clockwork mechanism has a baseplate; said baseplate is provided with a pivot-bearing pin extending normally therefrom; and said second portion of said shaft is formed with an axially extending bore which is slidingly and rotatingly mounted on said pivot bearing pin. 5. A clockwork mechanism according to claim l wherein:

said clockwork is provided with a rear wall having an aperture for the insertion of said shaft; said knob being formed with a collar portion which abuts the surface of said rear wall defining said aperture whereby dust is prevented from entering said clockwork mechanism through said aperture. 6. in a clockwork mechanism according to claim 5 wherein said shaft, said knob, said baseplate and said rear wall comprise a plastic material. 

1. In a clockwork mechanism having hands adjustable by a shaft assembly, said shaft assembly comprising: a shaft; a knob; said knob being releasably coupled to a first portion of said shaft, said knob being formed with an axial bore, and said knob having abutment means extending generally transversely of said axial bore; mutually abuttable first and second surface means carried by said shaft and said knob respectively and operable, in response to mutual abutment therebetween, to prevent rotational movement of said knob relative to said shaft in each of opposite directions of knob rotation; said shaft being formed with radially expanding means; said radially expanding means being provided with locking means, said locking means being lockingly engageable with said transversely extending abutment means to prevent axial movement of said knob relative to said shaft and permit axial movement of said knob to induce axial movement of said shaft, and said locking means being operably accessible at an outer end of said axial bore of said knob when said knob is mounted on said shaft.
 2. A clockwork mechanism according to claim 1 wherein: said first portion of said shaft is provided with a longitudinal slot to form two expandable resilient projections, which projections define said locking means; the terminal ends of said projections are formed with radially extendinG portions whereby said projections are generally hooklike in configuration; and said axial bore in said knob is formed with an internal shoulder, defining said abutment means, for lockingly retaining the radially extending portions of the terminal ends of said projections when said knob is mounted on said shaft.
 3. A clockwork mechanism according to claim 2: wherein each said radially extending portion of each said projection is formed with a partial frustoconical surface tapered toward the terminal end of each said projection whereby said resilient projections are forced together by a wedging action on said surfaces by the internal surface of said knob defining said axial bore as said shaft is forced into said axial bore of said knob; and wherein a tool may be inserted within said axial bore to engage said frustoconical surfaces of said projections to force said projections together to disengage said projections from within said axial bore.
 4. In a clockwork mechanism according to claim 1 wherein: said shaft assembly is axially shiftable; a second portion of said shaft is formed with a pinion drive portion; said pinion drive portion being alternately engageable with an alarm-adjusting gearwheel and a time-indicating hand adjustment as said shaft is axially shifted; said clockwork mechanism has a baseplate; said baseplate is provided with a pivot-bearing pin extending normally therefrom; and said second portion of said shaft is formed with an axially extending bore which is slidingly and rotatingly mounted on said pivot bearing pin.
 5. A clockwork mechanism according to claim 1 wherein: said clockwork is provided with a rear wall having an aperture for the insertion of said shaft; said knob being formed with a collar portion which abuts the surface of said rear wall defining said aperture whereby dust is prevented from entering said clockwork mechanism through said aperture.
 6. In a clockwork mechanism according to claim 5 wherein said shaft, said knob, said baseplate and said rear wall comprise a plastic material. 